June 11, 2008
Summary
Microsoft policies and practices continue to fall short of enabling customers to fully realize the benefits of virtualization as a core infrastructure technology. This updated paper highlights changes in Microsoft practices since April 2007, as well as issues that remain to be addressed as of June 2008.
1. Support for Customers
Situation: Microsoft commits to provide "commercially reasonable" support to their Premier-level support customers using Microsoft products in virtual machines. Unfortunately, this commitment is sometimes misunderstood by Microsoft personnel. As a result, the corporate policy is not always accurately communicated to customers that need this service.
In contrast, many major software vendors have chosen to clearly state that they provide at least commercially reasonable or "best effort" support for all of their customers, not just those customers at premium contract tiers.
Impact: Some Premier-level support customers receive excellent support for Microsoft products running on a VMware platform. Others encounter resistance from Microsoft when they request assistance. It is common for customers who don’t initially get the help they expect from Microsoft to seek and receive Microsoft managerial commitment for support. These escalations are very effective and resolve any issues around support of Microsoft products on virtual platforms. Unfortunately, this is also a frustrating (and unnecessary) experience for customers who have already purchased premium-level support services.
Customers using virtual platforms who do not have a Microsoft Premier-level support agreement still have no clear commitment of Microsoft support. Microsoft support specialists may request that these customers replicate an issue on a physical machine before accepting a support request. Customers that don’t wish to contract for premium support services must tolerate this ambiguous situation, or rely on other trusted partners for assistance as they deploy virtualization.
Microsoft announced their intent to provide a cooperative technical support mechanism to all customers running Windows Server on qualified hypervisor platforms in November, 2007 through the Server Virtualization Validation Program (SVVP). This program was launched in June, 2008.
VMware believes the SVVP to be a positive step toward more comprehensive customer support, although it fails to address support for all Microsoft Server products. VMware is working with Microsoft to resolve technical and commercial elements of the program, and hopes that this will lead to VMware participation.
2. Prohibitions on Commercial Distribution of Microsoft Virtual Machines
Situation: Microsoft offers a portfolio of “Test Drive” virtual machines packaged in Microsoft's VHD format. These "VHDs" are free for use by anyone wishing to run selected products on a trial, non-production basis. VHDs are also used by independent software vendors to configure and deliver their own products in pre-built demonstration machines.
Microsoft does not allow third parties to choose the Microsoft products they want to demonstrate in Windows-based virtual machines and furthermore, Microsoft’s VHDs are the only permissible building-block for permitted Microsoft product demos. Third parties are also not allowed to distribute VHDs for production purposes in any situation.
In addition, Microsoft policy further precludes any model that would effectively enable software vendors to sell any Windows-based virtual machines for production use in commercially useful volumes.
Impact: Delivering demonstration software based on Windows and other Microsoft products is important to hardware and software vendors, given Microsoft’s very significant presence in a number of software markets. Offering production-ready virtual appliances is a growing business model. Limiting the use of Windows-based virtual machines to demonstration-only products that are selected by Microsoft prevents the growth of a market that customers and software vendors increasingly seek to address.
In contrast, VMware announced in April 2006 that its virtual machine disk format, VMDK, was made openly available on its website. Since then, over 2000 vendors and developers have requested to review and use the VMDK..
VMware started a virtual appliance initiative in 2005. Today there are over 750 virtual appliances available on the VMware Virtual Appliance Marketplace, including Oracle databases, CRM packages, internet firewalls, email security solutions and operating systems like Red Hat Enterprise Linux. The selection of appliances includes demonstrations and production-ready products, some free and some for sale. Any of these appliances can be used as-is, or converted for use on any virtualization platform. Customers download tens of thousands of units from the Marketplace weekly. Microsoft and the entire ecosystem of Microsoft ISVs and partners could benefit from Microsoft’s support of this business model.
3. Limitations on Translation of Microsoft VMs into Other Formats
Situation: Microsoft’s VHD portfolio is free for use by anyone wishing to run the packaged products on a trial, non-production basis. Microsoft has indicated that end-users are allowed to convert these VHD virtual machines to the non-VHD format of their choice, but language in the current End User License Agreement that accompanies several of these “Test Drive” virtual machines states does not explicitly make this grant. Instead, it states “You may install and use the software on your device on which you are running any virtualization software able to run Virtual Hard Disk (VHD) formats... “.
At least one of these agreements states “You may not convert the virtual hard disk image from the VHD format.” In another case, Microsoft states that the use of their Virtual Server product is a requirement.
Additionally, third parties using VHDs to deliver Windows-based virtual machines for demonstration purposes are not allowed to convert their demonstration VHD virtual machines into other formats, regardless of their customer’s needs. Virtual appliances containing Microsoft product must be distributed in Microsoft’s VHD format.
Impact: The ability to run free Microsoft demonstration products is important to customers. This ability should be clearly permitted on any virtualization platform chosen by a customer. Delivering free demonstration software based on Windows and other Microsoft products is important to hardware and software vendors. Limiting this distribution to a single virtualization format inhibits choice in the ecosystem as new business models are enabled by virtualization.
4. Server Virtual Machine Mobility
Situation: One of the most valuable benefits of virtualization is the ability to move virtual machines from one hardware platform to another without an interruption in operation, loss of network connection, etc. Most customers virtualizing servers actively use capabilities such as VMware’s VMotion and Distributed Resource Scheduling to balance resources and load, reduce the impact of hardware downtime, and create a more scalable, resilient IT infrastructure.
Microsoft licensing policies allow "instances" of Windows and server applications running in virtual machines to be moved from one physical server to another at will, as long as the original and destination server are both properly licensed. "Moving an instance of software” requires that any hardware used to run the instance be licensed for the products in that instance at all times, even though the instance may only run on some hardware infrequently. Microsoft further restricts re-assignment of licenses from one server to another to once only per 90 days, except in case of permanent hardware failure. Microsoft licenses are tied to physical hosts and do not “move” with virtual machines.
For example, a customer with two virtualized servers can use VMotion to move a virtual machine containing both Windows Server 2003 and Exchange 2003 from the primary server to a secondary in order to perform maintenance on the primary. Microsoft’s license requires that each physical server is assigned its own license for Windows Server 2003 and Exchange 2003.
Impact: Microsoft license policies remain unchanged since 2007, and effectively require that customers choose between two unappealing options:
- Customers who could otherwise use VMotion to prevent application downtime by moving workloads from a server that is overloaded, is failing or needs to be upgraded, must either:
- Reassign licenses to allow the move, and wait 90 days before the next move can take place, or
- For licenses have been reassigned during the previous 90 days, the customer must intend to retire the machine in order to re-assign the licenses. A customer’s interest in repairing a machine and returning it to service is not accomodated.
- Customers who wish to use VMotion to move workloads to avoid downtime, address variable demand, or ensure operational flexibility must assign more licenses than the same application requires to run the same workload in a physical environment.
Microsoft licensing terms do not yet fully enable the benefits of virtualization based mobility. Customers should understand the restrictions of existing Microsoft license terms to ensure their ability to negotiate their own agreements effectively. Without this knowledge, customers risk paying more to license the same applications than they did in an otherwise-identical physical computing infrastructure.
5. Limitation on Desktop Virtualization
Situation: Users of Windows Vista in a virtual environment may not utilize any content protected by Microsoft digital, information, or enterprise rights management technology, thereby reducing the value of Windows running in a virtual machine. Microsoft states “Should the security of the host operating system be compromised, it is not possible to ensure the protection of digitally protected content or applications.” This greatly exaggerates the risk of compromise, and lacks any foundation in practical application.
Additionally, in April 2007 Microsoft announced a licensing model to support server-based hosting of virtualized Windows desktops, called Windows Vista Enterprise Centralized Desktops (VECD). VECD allows customers to deploy and run Windows Vista Enterprise in virtual machines on server hardware, and access them using remote PCs and thin clients. VECD is available only to customers purchasing Vista Enterprise and a Microsoft Software Assurance contract, plus an annual, per-device subscription fee. The “downgrade rights” available under a Software Assurance agreement allow VECD customers to deploy any version of Windows Professional edition (Windows 2000 Professional, XP Professional, and Vista Enterprise) in a virtual machine.
Finally, in early 2008, Microsoft announced that Vista Home Basic and Home Premium editions could be virtualized, making the license terms consistent with the more expensive editions of Windows Vista. VMware applauds this step toward enabling home users to enjoy the benefits of virtualization.
Impact: Microsoft precludes the use of a valuable feature of Windows Vista in virtual machines based on exaggerated claims of security risks that have no basis in practical application. These claims serve to confuse customers and limit adoption of virtual technology on the desktop.
The VECD program is a positive step, but imposes a significant cost premium versus other software distribution options for customers working to deploy a virtual desktop infrastructure that leverages the features and capabilities of leading-edge virtualization platforms. Further, it prevents customers from realizing the promise of delivering a consistent desktop to a location-independent or highly-mobile worker by tying the license to each physical PC.
6. Windows Virtualization APIs
Situation: Microsoft has developed proprietary APIs that include software Microsoft calls “Enlightenments” for Windows Server 2008. These APIs facilitate communication between Windows and Microsoft’s hypervisor, and provide performance improvements for hypervisors that incorporate this technology.
Microsoft disclosed an early version of these API specifications at the Windows Hardware Engineering Conference (WinHEC) in June 2006 under terms that prohibited development or testing. Novell was granted an exception to this limitation, as part of an agreement that gave Microsoft critical operating system intellectual property rights and ongoing payments.
Microsoft subsequently disclosed a later version to VMware in August 2007, and allowed internal testing and characterization. Microsoft also delivered a later version of these specifications to the public under an “Open Specification Promise” (OSP) in October 2007. The OSP takes the form of a “personal promise” to allow others to implement the required portions of the covered specification. Significant questions on the actual extent of the license rights granted under this promise have been raised and continue to be debated.
A final version of this technology is not yet available.
Impact: The actual extent of the grants provided by the OSP are uncertain for potential licensees. There is no consistently accepted view on any software vendor’s real ability to freely utilize this technology at parity with Microsoft in the long term. Access to this critical technology remains questionable for broad use/implementation by commercial developers.
In contrast, VMware has participated and contributed heavily to open community work that implements paravirtualization APIs for any virtualization platform and any OS. This paravirtualization technology is freely available and is being broadly adopted by Linux, Xen, KVM, etc.